One of the common difficulties in performing bio-assays is preparing a sample for testing. Raw samples can be obtained from a bodily fluid, bodily waste, or from a swab that is subsequently placed in a buffer solution to release collected cells, DNA, and varying amounts of extraneous matter collected during the swabbing. Current sample preparation techniques can be expensive, labor intensive, time consuming, and can rely heavily on human participation.
Preparation of raw samples for testing typically includes clean up steps, such as forcing the sample through various sizes and types of filters to trap, isolate, screen, or sort out particles that range down to micron and sub-micron sizes. During preparation, samples can be contaminated or otherwise rendered unusable due to handling or simple human error. Proper sample concentration and clean-up reduces clogging especially when used with micro-scale structures.
The recent arrival of point of care devices for use in clinics and doctors' offices has increased the need for a simple, yet robust preparation device that a non-technician can use to perform the critical step of sample preparation at the ‘point of care.’ This creates an intense need for a device to simplify sample preparation and concentration while maintaining the integrity of the sample.
Current sample preparation and concentration methods usually involve a syringe and a single size filter for each clean up step. Such filters utilize a single direction of fluid flow, and are typically operated using the injection stroke of a syringe to filter out large particles. The sample is filtered through different, successively smaller filters such as by fitting the filters to a different syringe. Each time the filter is changed, technician time increases and the possibility of sample contamination also increases.